<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>

    #d1{
        width: 100px;height: 100px;
        border: 1px solid red;
        /*单独某个方向添加外边距*/
        margin-left: 50px;
        margin-top: 50px;
        margin-bottom: 30px;
        margin-right: 100px;
        /*四个方向添加外边距*/
        margin: 50px;
        /*上下和左右赋值*/
        margin: 50px 100px;
        /*上下0 左右自动(居中)*/
        margin: 0 auto;
        /*上右下左 顺时针赋值*/
        margin: 10px 20px 30px 40px;
    }
    #d2{
        width: 100px;height: 100px;
        border: 1px solid red;
        /*上下相邻的两个元素彼此添加外边距,取最大值*/
        margin-top: 50px;
    }
    span{border: 1px solid blue}
    /*行内元素上下外边距无效*/
    #s1{margin-right: 50px}
    /*左右相邻彼此添加外边距,两者相加*/
    #s2{margin-left: 50px}
    #big{
        width: 200px;height: 200px;
        background-color: red;
        overflow: hidden;/*解决粘连问题*/
    }
    #big>div{
        width: 50px;height: 50px;
        background-color: green;
        margin-left: 100px;
        /*当元素的上边缘和上级元素的上边缘重叠时,给元素添加上外边距
        会出现粘连问题,给上级元素添加overflow:hidden解决*/
        margin-top:100px;

    }
  </style>
</head>
<body>
<div id="big">
    <div></div>
</div>
<span id="s1">span1</span><span id="s2">span2</span>
<div id="d1">div1</div>
<div id="d2">div2</div>
</body>
</html>